Tone burst generator

ABSTRACT

The present invention is a tone burst generator that provides periodic tone bursts or high frequency signals of a predetermined time duration at periodic intervals. The device includes a time duration and interval control section that determines the burst duration and repetition rate. The output of this section is applied to a drive control section which controls a drive and feedback section. The drive and feedback section drives a load section which includes the secondary of a transformer and a transducer. The drive and feedback section feeds back signals, at the tone rate, to the drive control section which controls the drive element in the drive and feedback section.

United States Patent [191 Lindstrum 1 1 TONE BURST GENERATOR [75] Inventor: Alan L. Lindstrum, Port Blakley,

Wash.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC

22 Filed: Aug. 2, 1973 21 App]. No.: 384,871

[52] U.S. C1 331/75, 331/107 R, 331/111,

331/117 R, 331/166 [51] Int. Cl. H03b 11/10, H03k 3/35 [58] Field of Search ..331/166,172-174,

[ 1 Mar. 25, 1975 3,480,880 11/1969 Starr, Jr. 331/166 X Primary ExaminerSiegfried H. Grimm Attorney, Agent, or FirmR. S. Sciascia; Charles D. B.

Curry [57] ABSTRACT drives a load section which includes the secondary of a transformer and a transducer. The drive and feed- [56] Ref Cit d back section feeds back signals, at the tone rate, to the UNITED STATES PATENTS drive control section which controls the drive element in the drive and feedback section. 3,297,963 1/1967 Halsted 331/166 X 3,316,502 4/1967 Karras 331/75 X 7 Claims, 2 Drawing Figures TIME DURATION AND LOAD INTERVAL CONTROL DRIVE AND SECTION DRIVE CONTROL SECTION FEEDBACK SECTION SECTION r A if 1? V A 1 65 l 39 r",- 23 e7 '1 T PNPN DIODE TONE BURST GENERATOR BACKGROUND OF THE INVENTION l. Field of the Invention The present invention relates to an oscillator device and more particularly to a tone burst generator for generating short periodic bursts or high frequency signals of predetermined time duration at periodic intervals.

2. Description of the Prior Art Prior tone burst generator devices have had the disadvantages of low efficiency, marginal reliability and were of relatively large size. This has been largely due to circuitry characteristics that consumed excessive power for biasing of transistors and using analog amplification techniques. The invention overcomes these disadvantages by saturated switching techniques and load sensitive feedback control.

SUMMARY OF THE INVENTION The present invention is a tone burst generator that provides periodic tone bursts or high frequency signals of a predetermined time duration at periodic intervals. The device includes a time duration and interval control section that determine the burst duration and repetition rate. the output of this section is applied to a drive control section which controls a drive and feedback section. The drive and feedback section drives a load section which includes the secondary of a transformer and a transducer. The drive and feedback section feeds back signals, at the tone rate, to the drive control section which controls the drive element in the drive and feedback section.

STATEMENT OF THE OBJECTS OF THE INVENTION An object of the present invention is to provide a tone burst generator that is efficient, small and reliable.

Another object of the present invention isto provide a tone burst generator that uses saturated switching techniques.

Still another object of the present invention is to provide a tone burst generator that employs a load sensitive feedback control.

Other objects, advantages and novel features of tlie present invention invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic drawing of the tone burst generator of'the present invention; and

FIG. 2 is-a drawing illustrating'the output'wave'form' of the tone burst generator of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 is illustrated the-tone burst gen'eratorl l of' the present invention. The primary function'of this invention is to provide periodic tonebursts or high frequency signals of a predetermined timed'uration at periodic intervals. ADzC. power source 13"is-used to'drive a sound transducer 1'5,.for example, bymeans of the tone burstgenerator circuitry. of the presentiinvention'.

As illustrated in'FlG. 2"tliis' circuitry generates a-hi'gh' frequency signal f havingatimedurationT .that sequentially occurs attimeintervals T As ill'ustratedin FIG. 1 one side of DC. source I3, which may be an 18 volt battery, is connected to ground and the other side is connected to the cathode of diode 17. The anode of diode 17 is connected in series through diode l9, resistor 21 and switch 23 to ground. Connected in parallel with diode 19 is capacitor 25 and capacitor 27, resistor 29, and resistor 31 are connected, as shown. A diode 33, which is preferably a PNPN 4-layer diode, is connected between capacitor 25 and resistor 29. Resistor 35 is connected in series with the base of transistor 37 and resistor 39 and capacitor 41 are connected in series with the base of transistor 43. Resistor 44 is connected across the base and emitter of transistor 43. Connected in series between the emitter of transistor 43 and the collector of transistor 37 is resistor 45. Resistor 47 is connected across transistor 37 and in series with capacitor 49 and resistor 51, which are connected in parallel across resistor 45. The base of transistor 43 is connected through diode 53 and resistor 55 to the primary winding 57 of transformer 59. The collector of transistor 43 is connected through resistor 61 to ground and to the base of transistor 63. The collector of transistor 63 is connected through diode 65 and resistor 66 to primary winding 57. Capacitor 67 is connected across DC power source 13 through diode 17 to store energy to reduce ripples on the supply line. Capacitors 69 and 71 are connected in parallel across secondary winding 73 of transformer'59. Transducer 15- is connected as the load across secondary winding 73 of transformer 59.

The operation of the tone burst generator 11 of FIG. 1 is as follows. Operation of the device is initiated by closing switch 23. When this occurs capacitor 25 charges through resistor 21. The time required to charge capacitor 25 is the time interval T of FIG. 2 and is determined by the selected parameters of DC. voltage source 13, resistor 21 and capacitor 25. When the voltage across capacitor 25' reaches 10' volts, for example, diode 33 switches on momentarily to transfer a charge to capacitor 27.

When diode 33 switches on transistors 37 and 43 are simultaneously switched on. Transistor 37 is held on for a time duration T of about 10 milliseconds, for example, as determined by the time constant of resistors 29 and 3-1 and capacitor 27. Transistor 43 remains on for only about 10 microseconds due to the limiting time constant of resistor 39 and capacitor 41. Transistor 43 biases transistor 63, which is the power output transistor, into saturation to provide a high current pulse to primary winding 57 of transformer 59 The tuned circuit consisting of the inductance of secondary winding 73 and the parallel capacitance of capacitors 69 and 71 andtransducer 1'5, begin to ring or oscillate because of the single pulse applied to the primary winding 57 when transistor 63 .is switched on. The parameters of the elements of the tuned circuit are preferably selected to providea singal f of about 45 kiloHertz, for example. The ringing also appears across primary winding 57 as a slightly dampened sinusoidal voltage having a frequency of 45 kiloHertz. One cycle after the start of the initial pulse applied to the primary the voltage at point A of the primary, minus the voltage drop across resistor 55' and' diode 53, has swung positive with respect to the base of transistor 43which'turns transistor 43'on. Transistor 43" and 63' remain on until the voltage at point A swings sufficiently negative to reverse bias diode 53. This process is repeated on every positive half cycle until transistor 37 turns off at the end of milliseconds. Thus the voltage across transducer is a 45 kilol-lertz sinusoidal tone burst of 10 milliseconds time duration T Transistor 63 operates as a saturated switch. To obtain high efficiency the turn-on and turn-off threshold points must be accurately controlled. Capacitor 49 charges to about 9 volts after several cycles and thus shifts the threshold point of the feedback loop. To maintain a drive pulse from transistor 63 that is symmetrical with respect to the positive half cycle output waveform the voltage across capacitor 49, and therefore the feedback threshold, increases slightly during the pulse. This compensates for storage time in transistor 63.

What is claimed is:

l. A tone burst generator comprising:

. a time duration and interval control section;

. a drive control section;

. a drive and feedback section;

. a load section including a tuned circuit;

. a power source;

said time duration and interval control section including a first diode, one side of said first diode connected to one side of said power source, the other side of said first diode connected through a first resistor to the other side of said power source, a first capacitor connected in parallel with said first diode, the anode of a 4-layer diode connected to one side of said first capacitor, a second capacitor, the cathode of said 4-layer diode connected through a second resistor and said second capacitor to the other side of said first capacitor;

g. the cathode of said 4-layer diode, said second resistor and said second capacitor of said time duration and interval control section being operatively connected to said drive control section, the output of which is operatively connected to said drive and feedback section, the output of which is operatively connected to said load section; and

h. said drive and feedback section including feedback means operatively connected to said drive control section, and drive means operatively connected to said load section.

2. The device of claim 1 wherein:

a. said drive control section includes a first transistor operatively connected to said second capacitor; and

b. a second transistor operatively connected through a third capacitor to said second capacitor.

3. The device of claim 2 wherein:

a. said drive means of said drive and feedback section includes a third transistor operatively connected to the primary winding of a transformer for providing a series of current pulses to said primary winding; and

b. said third transistor being operatively connected to the output of said second transistor.

4. The device of claim 3 wherein:

a. said feedback means of said drive and feedback section operatively connecting said primary winding to the input of said second transistor.

5. The device of claim 4 wherein:

a. said feedback means includes a third resistor and a diode.

6. The device of claim 5 wherein:

a. said tuned circuit includes the secondary winding of said transformer, and fourth and fifth capacitors and load means connected in parallel across said secondary winding.

7. The device of claim 1 wherein:

a. said load section provides an oscillating tone signal; 4

b. said feedback means controlling said drive control section at the frequency of said tone signal; and

c. said control section controlling the drive element of said drive and feedback section to drive said load section at the frequency of said tone signal. 

1. A tone burst generator comprising: a. a time duration and interval control section; b. a drive control section; c. a drive and feedback section; d. a load section including a tuned circuit; e. a power source; f. said time duration and interval control section including a first diode, one side of said first diode connected to one side of said power source, the other side of said first diode connected through a first resistor to the other side of said power source, a first capacitor connected in parallel with said first diode, the anode of a 4-layer diode connected to one side of said first capacitor, a second capacitor, the cathode of said 4-layer diode connected through a second resistor and said second capacitor to the other side of said first capacitor; g. the cathode of said 4-layer diode, said second resistor and said second capacitor of said time duration and interval control section being operatively connected to said drive control section, the output of which is operatively connected to said drive and feedback section, the output of which is operatively connected to said load section; and h. said drive and feedback section including feedback means operatively connected to said drive control section, and drive means operatively connected to said load section.
 2. The device of claim 1 wherein: a. said drive control section includes a first transistor operatively connected to said second capacitor; and b. a second transistor operatively connected through a third capacitor to said second capacitor.
 3. The device of claim 2 wherein: a. said drive means of said drive and feedback section includes a third transistor operatively connected to the primary winding of a transformer for providing a series of current pulses to said primary winding; and b. said third transistor being operatively connected to the output of said second transistor.
 4. The device of claim 3 wherein: a. said feedback means of said drive and feedback section operatively connecting said primary winding to the input of said second transistor.
 5. The device of claim 4 wherein: a. said feedback means includes a third resistor and a diode.
 6. The device of claim 5 wherein: a. said tuned circuit includes the secondary winding of said transformer, and fourth and fifth capacitors and load means connected in parallel across said secondary winding.
 7. The device of claim 1 wherein: a. said load section provides an oscillating tone signal; b. said feedback means controlling said drive control section at the frequency of said tone signal; and c. said control section controlling the drive element of said drive and feedback section to drive said load section at the frequency of said tone signal. 